The Molecular and Physiological Mechanisms of Microbial Survival in Antarctic Lakes

Full description

Metadata record for data expected from ASAC Project 1152
See the link below for public details on this project.

---- Public Summary from Project ----
The small ice-free areas of Antarctica carry a remarkable range of lakes. Within the Vestfold Hills there are several hundred lakes and ponds, many of which are saline. All Antarctic freshwater and saline lakes have simple food webs that are dominated by micro-organisms (bacteria, algae and protozoa). There are no fish and very few zooplankton. These micro-organisms have evolved novel biochemicals and physiological adaptations which enable them to survive and function at sub-zero temperatures in saline lake waters. For example previous work has shown that many of the bacteria contain antifreeze proteins which prevent the cell contents from freezing. If these bacteria have invested in the evolution of antifreeze proteins they must also have developed suites of low temperatures enzymes which mediate routine cellular functions. One aspect of this project will concentrate on identifying such enzymes and quantifying their activity in different bacterial species, which will be identified using modern molecular techniques. Thus the outcome will be a picture of what enzymes occur, and which bacterial groups possess them. Low temperature enzymes have many potential industrial uses and it is hoped that some of the enzymes identified may be developed by industry. The commercial application of some low temperature enzymes, e.g. lipases, are presently being trialled

Our previous work in Vestfold Hills has shown that during the Antarctic winter many of the most successful and abundant protozoans maintain active populations, so that when the brief austral summer arrives 'they hit the deck running'. In order to do this many of them possess extraordinary nutritional versatility. They are able to undertake photosynthesis like plants and eat bacteria. As day length and the light climate change in the annual cycle, such species switch from a dependence on photosynthesis in summer, to feeding on bacteria in winter. We propose investigating this phenomenon, known as mixotrophy, in a number of the dominant species (Pyramimonas and Cryptomonas) in several of the saline lakes within the Vestfold Hills. This work will contribute to understanding how pristine Antarctic lake ecosystems function; information which is fundamental to monitoring changes induced by climate change. It has recently been reported that environmental warming alters food web structure and trophic interactions (Petchy et al., 1999). These delicate ecosystems are likely to show rapid response to climatic perturbations, indeed long-term work in the Dry Valleys of Southern Victoria Land has demonstrated that Antarctic lakes are responding markedly to climate change.

The download file contains an excel spreadsheet of data from Ace Lake and Highway Lake, as well as two word documents, one containing further data, and another containing details on the methods used in the data collection and analysis.

The fields in this dataset are:

Date
Depth
Chlamydomonas
Cryptophyte
Heterotrophic bacteria
Heterotrophic nanoflagellates
Ciliate Mesodinium
Paralabidocera
Pyramimonas
Daphniopsis
Chlorophyll a

Lineage

Progress Code: completed